Fuel supplying means using crankcase pressure developed in a twocycle engine for delivering fuel to the carburetor



Oct. 27, 1953 -w. c. CONOVER 2,656,828

FUEL SUPPLYING MEANS usmc CRANKCASE PRESSURE DEVELOPED IN A wwowycua ENGINE FOR DELIVERING FUEL TO THE CARBURETOR 4 Sheefis-Sheet 1 Filed Oct. 1, 1949 WAR/KEN c. couove/g 4M,

attorneys Oct. 27, 1953 w. CONOVER 5 FUEL SUPPLYING MEANS USING GRAN SE PRESSURE PED R DEVELO IN A TWO-CYCLE E NE DELIVERING FUEL TO THE CARBURE Filed Oct. 1, 1949 4 Sheets$hee't 2 I Juventcr WHERE/V C CONOVER attorneys Oct. 27, 1953 w. c. CONOVER 5 8 FUEL SUFPLYING MEANS USING CRANKCASE PRESSURE DEVELOPED IN A TWO-CYCLE ENGINE FOR DELIVERING FUEL. TO THE CARBURETOR 4 Sheets-Sheet 3 Filed Oct. 1,1949

1 I In? ISnuentor Qttornegs Oct. 27, 1953 w. c. CONOVER 2,656,828 FUEL SUPPLYING MEANS usms CRANKCASE PRESSURE DEVELOPED IN A TWO-CYCLE ENGINE'FOR DELIVERING FUEL TO THE CARBURETOR Filed Oct. 1, 1949 4 Sheets-Sheet 4 3nventor (Iltorneg:

Patented Oct. 27, 1953 UNITED STATES PATENT OFFICE Warren G. Conover, Waukegan, Ill., assignor to Outboard, Marine & Manufacturing Company, Waukegan, 111., a corporation of Delaware Application October 1, 1949, Serial No. 119,085

18 Claims.

This invention relates to a fuel supplying means using crank case pressure developed in a two-cycle engine for delivering fuel to the carburetor of such engine.

Cross reference is made to my co-pending ap plications Serial No. 276,021 and Serial No. 276,- 022, filed March 11, 1952.

It has been the general practice in the outboard motor industry to make the fuel tank a unitary part of the power head structure. Size and weight limitations have made it necessary that the tank have limited fuel capacity, thus requiring relatively frequent filling, an operation which, in rough water, frequently involves the spilling of fuel, the fouling of the fuel tank and much inherent waste and danger. It is, therefore, the major object of the present invention to provide a fuel tank which will be separate from the power head and, although connected therewith for use, may be readily separated from the power head for independent transportation. In providing such a fuel tank, the weight of the outboard motor as such is greatly reduced, thus facilitating transportation and mounting and dismounting; the size of the fuel tank may be greatly increased, thus minimizing fuel replacement on the open water; the introduction of foreign matter into the fuel tank is made unlikely; and the spilling and fire hazard is virtually eliminated.

In order to make the fuel feed automatically from a remote fuel tank to the prime mover of the outboard motor, the present invention makes use of the fact that the engines ordinarily powei ing outboard motors are two-cycle engines in which the combustible mixture is compressed in the crank case preliminary to its delivery to the combustion chamber in the cylinder. It is an object of this invention to provide means for the controlled delivery of crank case compression to the surface of the fuel in the remote tank thereby creating a pressure differential sufficient to cause the fuel to flow from the remote tank to the carburetor of the engine for use.

In order effectively to accomplish the aforesaid objectives, it is a further purpose of the present invention to provide a novel and improved organization of the crank case, the carburetor and valve controlled connections to the remote fuel tank.

Still other objects of the invention will appear more fully from the following disclosure, having reference to the accompanying drawings, in which:

Fig. 1 is a view in perspective of a remote fuel tank used for the purposes of the present invention, portions of the associated engine and carburetor being diagrammatically illustrated, partially in side elevation and partially in section.

Fig. 2 is a. greatly enlarged fragmentary detail view in perspective of the fuel tank shown in Fig. 1, portions thereof be'ing broken away to expose the interior construction.

Fig. 3 is a fragmentary detail view in axial section of a priming pump incorporated in the fuel tank.

Fig. 4 is a bottom plan view of the pump shown in Fig. 3.

Fig. 5 is a view partially in perspectiveand partially in transverse section showing a mounting arrangement for the priming pump and fuel and pressure supply connections from and to the fuel tank.

Fig. 6 is a view in side elevation of component crank case, valve plate and carburetor parts as they appear when separated.

Fig. 7 is a detail view taken in section on an enlarged scale on the plane indicated at 'l--'! in Fig. 6.

Fig. 8 is a view taken in longitudinal section through the separable communication line coupling on the axis of one of the communication conduits.

Fig. 9 is a view taken in transverse section on the line 99 of Fig. 8.

Fig. 10 is a detail view of one of the coupling elements in side elevation with portions thereof broken away to an axial section to show the seating of a check valve thereof.

Fig. 11 is a view in perspective diagrammatically illustrating in position on a boat an outboard motor equipped with the present invention, the

communication coupling between the motor and fuel tank having been broken.

Fig. l diagrammatically illustrates how the invention operates. The two-cycle engine 15, here shown as having two alternately firing cylinders [6, I1, and separate crank cases 18 and I8, respectively, in which the combustible mixture is compressed for delivery to the cylinders in the usual manner, has a carburetor 20 with float chamber 21 to which a pipe 22 leads from the coupling element 23 which is desirably attached by bracket 24 to the engine. The complementary coupling element 25, detachably engaged with coupling element 23, provides an extension 26 of pipe 22 which is connected by hose 2'! with the fuel supply tank 30 in a manner hereinafter to be described.

In order to supply pressure to the fuel. tank 33 for the delivery of fuel therefrom through hose 2'? and pipe 22 to the carburetor, a check valve arrangement allows pressure to be communicated from the respective crank cases to a pressure chamber 3| mounted on the engine and communicating through pipe 32,. coupling elements 723 and 25., extension pipe 33 and hose 34 with the fuel tank 30.

The fuel tank is shown in detail in Fig. 2-

and parts thereof are separately illustrated in Figs. 3 to 5. The tank comprises side wall portions 35, a bottom 35 and a top 3.1. The latter is positioned materially below the top of the side wall portions 35, the side wall portions overhanging at 38 to provide a recess. clearly shown. in Figs. 1 and 2 in which the dual hoses 21 and $4 1 are conveniently coiled when not in actual use. The top of the tank is desirably drained by ports Hi shown in Fig. l and Fig. 2, these being located at the ends only to drain off water or fuel spillage without soiling the sides, which in carrying, may

contactthe. operators; clothing. These. hoses, incidentally, are desirably united byunitar-ily molding their rubber or synthetic rubber-jackets together throughout the greater portions of the hose lengths, separating the respective hoses only at their ends where they are attached to their respective couplings.

Fixed in the top wall is any suitable filling cap, the particular arrangement shown comprising a sleeve 39 mounted in the top wall and threaded to receive the cap 40 which, as best shown in Fig. 1, may be flanged for convenient manipulation.

Separately prefabricated and mounted in the top wall for unitary assembly with the tank is a plate 6| which carries a gage mechanism 42 of vide a valve chamber 48, a pump chamber 49 and valve chamber 50. The part 45 provides valve seats 5| and 52 for the valves 53, 54, which operate in the valve chambers 48 and 510, respectively. The opening through the valve seat 5| communicates with an inlet chamber 55, which is also formed as a cavity in thecasing member 45. Access of the fuel to this chamber is permitted through a screen 55 which closes the bottom of the cavity.

The entire casing 44 is rigidly mounted by a tube'43 from the plate 4|. Through this tube extends the pump operating plunger 51, the handle se of which is exposed for manipulation by the operator. At its lower end, the-plunger 51 is conventionally connected with the diaphragm and is normally biased toward the upward position in which it is shown in Fig. 3 by a compression spring 59 pocketed in the lower casing memher 45 and acting upwardly upon the diaphragm. A port at leads from the valvechamber'48 to the pump chamber 49 and a port 6| leads from the pump chamber to a conduit 62 which opens through the valve seat 52 into valve chamber 50. From this point, a pipe 63 leads upwardly and, subject to control by a manually operable valve The pump casing 4.41 (Fig. 3). com- 4 64, this pipe communicates with the fuel line 34 as shown in Fig. 5.

Manipulation of the pump plunger draws fuel through the screen into chamber and thence past the valve seat 5| and check valve. 53 into chamber cs, from which the fuel flows through port 55 to the pump chamber 49 beneath the diaphragm. As the diaphragm is pushed down wardly by the plunger, it displaces the fuel from the pump chamber 45, check valve 53 being closed checkvalve 54 open, whereby the fuel passes through duct 5| and conduit 62 past the seat 52, check valve 54 to the fuel delivery pipe 63 and thence through. the fuel line 34 to the carburetor bowl. The construction is such that when the engine is running and the tank is subjected to pressure in themanner hereinafter described, the pressure differential between the tank and the carburetor bowl causes the fuel to flow on identically the same path, opening the check valves 53 and 54 and passing through pipe 63 and fuel hose as to the; carburetor independently of pump Operation,

The arrangement best shown in Figs. 6, and '2 (cf. Fig. 1) greatly facilitates the making of the various connections to the engine proper. Fig. 6 shows the actual preferred construction, whereas l is, diagrammatic.

Although the cylinders l6 and happen. to. be vertically superimposed in the engine chosen. for exemplification, the ports 65, 55 which communicate with the respective crank cases l8 and I9 are disposed on. an oblique, line for convenience of assembly. These ports are the fuel mixture inlet ports. These ports are respectively encircled by the gasket 51 which has openings regis tering with the ports and is also provided with openings 6.8, and, 5,9 to which, respectively, ducts l0 and H, lead from the respective. crank. cases.

Over the gasket 6,! is. applied thevalveplate 7.5, also shown in Fig. 6. and Fig. '7. This plate is laid, over the gasket without inversion from the position of Fig. 6; its'valve ports '16 and 11 being respectively in communication with the gasket openings 68- and 69: at points relatively, remote from the ducts Ill and H as best shown in Fig. 1-. A single piece of rubber; reenforced by a flat spring 18,. the spring and the rubber both being anchored by central bolts at 19, provides flap type check valves 80, and BI, respectively, which cover the valve ports 15 and 11. Since the respective crank cases are, alternately subject. to compression, and since the valves, andBl open outwardly in response to crank case compression, it will be evident that these valves will open alternately to communicate crank case compression to thecommon pressure chamber 3| previously described. This pressure chamber may desirably constitute av cavity in the carburetor mounting plate. 83. which, in Fig. 6, is shown in its inverted position after removal from plate 15.

The same. mounting plate 33 has cavities 84 and 85 with which the mixture port 86 from the carburetor communicates. The respective chambers84 and B5 overlie, respectively, annularseries of ports 81 and 38 in thevalve plate 15 for the controlled admission of mixture into the respective crank cases. The cavities 84 and 85 in the carburetor mounting plate 83 do not need to correspond in cross section with the ports 65 and E5 in the crank case because there is an intervening gasket 90 which has openings at 9| and 92' sufficiently large to provide communication to; all of the ports 8! and 88 respectively;

Behind plate I5, and disposed in the openings 65 and B6 of the motor block, are special mixture inlet check valves 89 which are shown only in dotted lines in the drawing of the valve plate I5 in Fig. but are more particularly described in a companion application. Any conventional check valve will suilice, so far as the disclosure of the present invention is concerned.

Thus air admitted through the carburetor 25, in the usual manner, is carbureted from fuel supplied to the carburetor bowl 2| through the fuel hose 34 from tank 38, such fuel being either pumped to the bowl or delivered to it by pressure which is communicated to the tank from the engine crank case or crank cases. The carbureted air enters the engine in any suitable manner, the two-cycle engine exemplifying the invention being supplied with mixture through its crank cases, as is usual. The flap valves 89 open to admit the air when the piston is moving outwardly in a given crank case and close as the piston returns, whereby pressure is created in the crank case. Tb transfer ports for delivering the compressed m ure from the crank case to the combustion chamber are not hown, having no relation to the present invention, and being conventional.

However, when any given crank case in a device embodying the invention is under compression, and until the tank 35 reaches equal pressure, a portion of the mixture from the crank casewill escape through the check valve 80 or 8| to the pressure chamber 31 from which pressure will be communicated as previously explained to the fuel tank 38 for maintaining a pressure differential which will effect continued delivery of fuel to the carburetor.

In the device disclosed, any blow back of flame is virtually impossible but, as a precaution, to prevent flame from being propagated from either crank case to the tank as, the pressure communication system includes the extremely flat, thin chambers 68 and t9 formed in the gasket 61, which provides parallel metal walls in close proximity to each other. In such a device, flame propagation is impossible because the metal will necessarily cool burning gases below the combustion point.

The device is fully operative regardless of any quickly separable connection in lines 21 and 34. However, in order to effectuate fully the objectives of the present invention, it is desirable to provide for ready connection and disconnection of such lines to the engines, and to this end coupling elements. 23 and 25 are employed. Reference has already been made to them. The preferred construction will now be described in detail,

The connector element 23, mounted on bracket is, may comprise simply a block .95 in which are mounted the male connector studs 96 and 97, stud 96 being typical and shown in section in Fig. 8. Each stud is tubular and provided with a nipple at 4 for the appropriate hose connection. Each stud is desirably closed at its outer end 98 except for a delivery port or ports at 9B which are so oriented respecting the outboard motor that any fuel remaining under residual pressure when the connector elements are separated will be discharged laterally, preferably sideward and downwardly outside the stern of a boat as indicated by the arrows in Fig. 11. The

- two ducts shown in Figs. 8 and 11 discharge sideward and downwardly respectively.

In addition to the male connector studs 96 and 91, the mounting block 95 carries a dowel I an outboard motor tank so are which is desirably provided with a pointed and shouldered head IDI with which engages the manually releasable detent I02 pivoted to connector element 25. The latter connecting element comprises a pair of chambers I03, IM, views in section through chamber I83 being shown in Figs. 8 and 10. Each chamber is provided with its own separate nipple It? for the respective hose connection, the nipple being screwed into the appropriate tube which projects from the rear of the chamber.

At the outer end of the chamber, there is an annular receiver I98 which is interiorly recessed to provide a suitable female seal, which may comprise the Q-ring I69. When the coupling elements are engaged, the appropriate male plug, such as plug 96, is received through the annular receiver I08 and is sealed by the O-ring. The closed end portion 98 of the plug, upon entering the receiver, thrusts aside the valve H6 and extends sufiiciently past washer Iii so that the ports 99 communicate with the interior of chamber 98. The valve H0 is mounted on a. guide H3 which, as best shown in Fig. 9, is of polygonal cross section to permit free flow around the guide. The guide member is socketed to receive the cornguide toward the position shown in Fig. 10, wherein the valve H0 is seated within the 0- "ing seal I99. Upon withdrawal of the male plug, the valve immediately seats itself to seal the appropriate hose from communication with the atmosphere. In the duplex connectors shown, the two hoses which lead to and from sealed simultaneously. They are also simultaneously placed in communication with the pressure and fuel delivery pipes 32 and 22 when the connector elements are reassembled, the detent I32 automatically holding the connector elements in mutually assembled engagement until manually released.

In the use of the device, it will be apparent that no greater pressures can ever be established in the tank 3i; than are developed in the crank cases is and I9. In the case of repeated crank case combustion sometimes occurring due to faulty carburetor adjustment or ignition faults, pre sures may become excessive. Therefore, to safeguard the tank against undue pressure increases, I provide a suitable safety valve which, in the device shown, comprises a disk I I5 of any suitable material such as synthetic rubber, which is normally held by a compression spring H5 and metal Washer I I 1 against a seat at i It around the vent aperture H9 The spring chamber is desirably vented laterally through port I 29 (Fig. 5) so that in the event that there should be any discharge from the tank, the force thereof will be expended harmlessly within the overhanging top flange within which the duplex hose is usually coiled when not in use.

Fig. 11 illustrates, somewhat conventionally, structure with the duplex hose in process of application thereto. When the connectors are secured together to complete the pressure and fuel supply connections between the tank and the outboard motor; a few strokes of the pump will deliver a sufficient quantity of fuel into the carburetor bowl to enable the outboard motor engine to be started. As soon as such on gine is started, and even during the preliminary cranking thereof, pressure will be communicated from the crank case or crank cases to the tank to establish a pressure differential which will in the mounting plate 4!.

continue to deliver fuel. through. the, check valves of the, pump and the intervening hose to the carburetor bowl. When the use of the outboard motor is terminated, and particularly if it is desired to remove the motor from the boat for transportation, the connector elements are separated, whereby any pressure remaining in the tank is sealed therein. No seal is required for those, connector parts which are attached to the motor because these are extremely short and the escape of a drop or two of liquid will release any pressure residual therein. The free ends of the hoses; are now coiled in the channel provided at the top of the fuel tank and the fuel tank, may thereupon be transported independentlyof the rest of the outboard motor structure.

The manufacture of the device is greatly simplified by reason of the fact that the pressure and fuel delivery terminals of the hoses are, at each end, comprised in prefabricated units which are capable of independent handling. Thus, at the upper end, the hoses connect to the mounting plate 83 which not only carries the carburetor but also provides communication with the crank case for the pressure line. At the lower end, the hoses connect to the mounting plate 4| upon which all parts extending into the tank are unitarily assembled.

I claim:

1. The combination with a two-cycle engine having a crank case in which pressure and vacuum are alternately developed as an incident to engine operation, of a remote fuel tank, a supply pipe from the tank to the engine and a pressure communicating conduit having a control valve and leading from said crank case to said tank for communicating to the tank pressure developed in said crank case, said control valve constituting means for closing said conduit when the crank case is under vacuum whereby the tank is continuously under pressure.

2. The combination with a two-cycle engine having a combustion cylinder and a separate mixture compression chamber, a carburetor, and a crank and piston for periodically compressing mixture in said chamber, of a remote and separate tank, a fuel delivery line from said tank to the carburetor having a flexible portion, and a pressure line from the chamber to the tank having a flexible portion and provided with a check valve opening outwardly of line for affording the communication of superatmospheric pressure from said chamber to said tank when the pressure developed in the chamber exceeds that of the tank.

3. The combination with a two-cycle engine having an intermittent mixture compression and decompression in the crank case, of a remote tank and a pressure line from the crank case to the tank provided with a valve chamber and a check valve opening outwardly from the crank case in the path of flow of mixture from the crank case toward the tank whereby said pressure line is in communication with the crank case only during mixture compression.

4. The device of claim 3 in, whichv said line includes a hose and a pair of separable connector elements, one of which is attached to the hose. 5. The device of claim 4 in which one of said elements comprises a male plug and the other an annular receiver having O-ring packing through which the plug is insertable, the element provided with the receiver also having a valve plug engageable in the O-ring packing alternatively with the maleplug and biased toward such engagement, the valve plug being in the said chamber in said path of introductionof the male plug to. be disengaged from the. O-ring packing upon insertion of the male; plug.

6'. In an outboard motor device, the combination with; an outboard motor comprising a. twocycle engine having intermittent mixture compression in its crank case and provided with a carburetor for the production of such mixture, a remote and separately portable fuel tank atv a level lower than said carburetor and provided with a sealed closure, a fuel line from said tank tothe. carburetor, and a pressure line from, the crank case to the tank, said pressure linev being providedwith a controlling valve opening for the communication, of maximum crank case pressure to said tank and having means for closing it when the crank case pressure interval has passed.

'1. The device of claim 6 in. which the respective. lines have separable connectors, whereby the tank may be wholly disassociatedfrom the outboard motor engine.

8. The device of. claim. '7 in which said connectors are dual, one such connector comprising a male. plug for each of said lines and the'other such connector providing receivers for the respective plugs.

9. The device of claim 8 in which the connector elementhaving therreceivershas O-rings constituting seals for the respective receivers and into which the respective male plugs. are insertable.

10. The device of claim 9 in which the connector having the said receivers is further provided with valve plugs normally engaged in the respec tive. O-rings and biased toward such engagement, the said valve plugs being in the path of the male plugs aforesaid to be displaced from the O-rings when, the male plugs are insertedtherein.

IL The, device of claim 10- in which one of the said connectors is provided. with a detent movably mounted thereon and provided with a handle for its manipulation, the other of said connectors having a latch device with which said detent is normally engaged in the assembly of said connectors.

12. In a device of the character described, the combination with a two-cycle internal combustion engine having periodic mixture compression in its crank case and provided with a carburetor for mixture formation, of a fuel tank, fuel and pressure lines. communicating with the tank and respectively communicating with the carburetor and the crank case and unitary mounting plates on the engine and the tank respectively, each of said mounting plates being provided with terminal connections for both lines.

13. The device of claim 12 wherein the mounting plate on the engine carries said carburetor and provides mixture delivery ports leading from the carburetor to the engine, and other ports leading from the engine crank case to the pressure line.

14. The: device of claim 13 in which a valve plate intervenes between the mounting plate and the engine and is provided with mixture and pressure ports and has inwardly opening mixture controlling check valve means regulating flow through the mixture ports and outwardly opening pressure controlling check valve means controlling mixture communication from the crank case to the tank.

15. The combination with a two-cycle internal combustion engine having periodic mixture compression in its crank case and provided with a carburetor for mixture formation, ofa fuel tank,

a pressure communicating line from the engine crank case to the fuel tank and a fuel return line from the fuel tank to the carburetor, the latter line comprising a pump chamber, receiving and delivery check valves at opposite sides of the pump chamber, and a displacement member manually operable in the pump chamber for fuel delivery from the tank to the carburetor pending development of pressure in said tank, fuel flow after tank pressure is developed occurring through said pump chamber and valves.

16. In a two-cycle internal combustion engine having a pair of separate crank cases provided with adjacent ports and separate ducts, a gasket applicable to the crank cases and providing separate pressure chambers with which such ducts communicate, a valve plate having ports registering with the crank case ports and pressure chambers and provided with inwardly opening valves for the crank case ports and outwardly opening valves leading from the pressure chamber, a mounting plate having chambers communieating with all of said valves, a carburetor having mixture forming passages communicating through the mounting plate with the inwardly opening valves aforesaid, and a pressure line having communication through the mounting plate to the outwardly opening valves aforesaid.

17. The combination with a two-cycle internal combustion engine having a crank case, a crank and piston for intermittently compressing mixture in the crank case and a carburetor for forming such mixture, the crank case having mixture inlet and outlet ports, a valve plate mounted on the crank case and having mixture inlet and mixture outlet valves controlling flow through the respective inlet and outlet ports of the crank case, and a mounting plate covering the valve plate and having mixture inlet and outlet passages communicating through the respective valves with the respective crank case ports, the carburetor being attached to the mounting plate in operative position to the mixture inlet ports, and a pressure supply line attached to the mounting plate and in operative connection therethrough with the mixture outlet port.

18. In an outboard motor having a remote fuel tank and a line leading thereto, the combination or said line with male and female connectors, the former comprising a plug in fixed connection with the outboard motor and having a lateral delivery port.

WARREN C. CONOVE'R.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,265,891 Ellis May 14, 1918 1,953,808 Kenneweg Apr. 3, 1934- 2,049,977 Ross Aug. 4, 1936 2,136,230 Berman Nov. 8, 1938 2,243,673 Henry Mar. 27, 1941 2,359,648 Jones Oct. 3, 1944 

